What if you could drive to the airport, hand your keys to a valet, get free parking for as long as you wanted, and have your car washed and cleaned? Oh, and you’d get a free gas card when you returned to pick it up.

A California start-up called FlightCar is testing the concept at San Francisco International Airport. There’s just one catch: While they have your car, they rent it out to other travelers.

It’s a fascinating new twist on so-called car-sharing, a business model that includes big companies such as Cambridge-based ZipCar­ (now part of Avis) and smaller start-ups like RelayRides — founded in Cambridge by a Harvard­ Business School alumnus but now based in San Francisco.

Cofounder Shri Ganeshram is taking time off from undergraduate studies at MIT to help launch the company; the three-person FlightCar team is participating in the Y Combinator accelerator program for entrepreneurs.

Ganeshram said the team noticed something basic about major airports: There’s usually a garage where departing travelers pay money to park, and another where arriving travelers pay to rent a car.

The founders — two of whom were high school students getting ready to head off to Harvard and Princeton — thought there might be synergy in combining those two businesses.

They have rented a warehouse near the San Francisco airport to hold 30 or 40 cars, Ganeshram said. Departing travelers who have registered with the site can call FlightCar while driving to the airport, where they will be met by a valet. He takes the keys, notes the gas level and mileage, and snaps a few pictures to document the condition of the car.

The company accepts only cars with mileage of less than 150,000, and nothing made before 1999. “They have to be generally rentable,” Ganeshram said. “We don’t want cars that people would be embarrassed to drive.”

FlightCar has $1 million in liability insurance and comprehensive collision and theft coverage, so the owner’s insurance “doesn’t get involved at all,” Ganeshram said.

FlightCar’s daily rental rate includes 90 miles; there’s a charge of 35 cents per mile after that, all of which goes to the vehicle owner.

When you return from your trip, you call FlightCar and they bring your vehicle back to the airport. Even though they have filled the tank to the level you left it at, you’re given a gas card worth at least $10. And even if the company has not managed to rent your car, the parking and valet service are free.

If things go well in San Francisco, Ganeshram said, the company plans to launch an operation in a second city this year. The possibilities include Boston, Los Angeles, and Seattle.

West Coast, East Coast

You do not often find MIT-spawned startups taking root in Los Angeles, but that’s what happened with Oblong Industries — in part because founder John Underkoffler had landed
gigs as a science adviser to Hollywood, consulting on movies such as “Minority Report” and “Iron Man.”

His work on new kinds of gestural interfaces, allowing people to use their hands to manipulate information on a screen, played a central part in “Minority Report” in 2002, and Oblong has been working to commercialize a system similar to the one Tom Cruise used in the film, now called g-speak. The firm is developing Mezzanine, a new kind of collaboration space that lets people share any kind of content from almost any device from any site.

Almost the entire Oblong team hails from MIT. The company has raised $9 million from investors that include Brad Feld, another MIT alumnus and a managing director at Foundry Group in Colorado.

Now the six-year-old firm has a presence in Boston’s Fort Point Channel neighborhood. It will be a hybrid of a demo center and small engineering outpost. Oblong’s chief executive, Kwin Kramer,
said the firm plans to hire more engineers here over time.